Heat exchange apparatus



Aug. 24, 1937.

V. O. MARSHALL HEAT EXCHANGE APPARATUS Filed March 14, 1956 4 Sheets-Sheet l )..IAI

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Aug. 24, 1937. v. o. MARSHALL I 2,091,003

HEAT EXCHANGE APPQRATUS Filed March 14, 1956 2 NW2 Q .UMMkH J 1 m Z 9 Y w /MMMWH /IIL Y a -fw/W! N MW m v. o. MARSHALL 2,091,003

Filed March 14, 1936 4 Sheets-Sheet 3 HEAT EXCHANGE APPARATUS Aug. 24, 1.937.

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a 30 gg 9 Aug. 24, 1937. v. o. MARSHALL HEAT EXCHANGE APPARATUS Filed March 14, 1936 I F GJ 3.

4 sheets-sheet 4 Patented Aug. 24, 1937 2.091.003 HEAT EXCHANGE APPARATUS Vivus O. Marshall, Mount Vernon, Ill., assgnor to J. P. Devine Manufacturing Co., Inc., Mount Vernon, Ill., a corporation of Illinois Application March 14, 1936, Serial No. 68,909

Claims.

'I'his invention relates to heat exchange apparatus, and with regard to certain more specific features, to heat exchange apparatus of the shell and tube type.

5 Among the several objects of the invention may be noted the provision of apparatus for exchanging heat between two iiuids, the said apparatus being dismountable for the purpose of cleaning and the like with maximum facility; the provision of heat exchange apparatus of the class described including eilicient baille means for providing for the circulation of one of the uids; the provision, in heat exchange apparatus of the class described, of a removable uid-directing baille plate which is nevertheless adapted to maintain a substantially sealed relation between itself and certain other elements of the apparatus; and the provision oi apparatus of the class described which is relatively simple and economical to construct and operate. Other objects will be in part obvious and in part pointed out hereinafter. l

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts which will be exemplified in the structures hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings, in which are illustrated several of various possible embodiments of the invention,

Fig. 1 is a longitudinal section of heat exchange apparatus `embodying the present invention; f

Fig. 2 is another longitudinal section of the apparatus of Fig. 1, taken along line 2--2 of Fig.

Fig. 3 is a cross section of the apparatus of Figures l and 2, taken along line 3-3 of Figure 2;

Fig. 4 is an enlargement of a fragment of Fig.

1; 2 -6 is an enlargement of a fragment of Fig. Fig. 7 is an end elevation ,of the apparatus shown in Fig. 6; Y y y Fig. 8 is a longitudinal section similar to Fig. 2, illustrating an alternative embodiment of` the invention;

Fig. 9 is a longitudinal section similar to Fig. 2, illustrating a second alternative embodiment of the invention;

Fig. 5 is an enlargement of a fragment of Fig.e

shown in Fig. 11; and, 5

Fig. 13 is a longitudinal section similar to Fig.

. 2, illustrating a third alternative embodiment of the. invention.

Similar reference characters indicate corresponding parts throughout the several views of 10 the drawings. 1

Referring now more particularly to Figs. 1 and 2, there is shown a' heat exchanger of the type to which the present invention relates. Basically, the heat exchanger comprises a shell l5 I in which are positioned a plurality or bundle of tubes 2 arranged in parallel relationship. This type of heat exchanger is commonly known as theshell and tube type, or surface type.

Such heat exchangers are used chiefly in trans- 20 ferring heat between two fluids, either of which may be a vapor or gas, or a liquid. For ex'- ampl, in oil rening operations, the exchanger is frequently' used for transferring heat between two liquids, while in steam power plants and in- 25 dustrial establishments, a heat exchanger of thisl type is frequently used for transferring heat 'between a liquid and a vapor or gas, such as steam.

One of the iluids enters the shell by way of an inlet 3 and leaves the shell by way of an outlet 30 4, the direction of flow of this fluid being regulated by a baille 5. 'I'he other uid enters the exchanger through an inlet 6 to a chamber 1, whence it passes through one group 8 of tubes 2 to a oating head 9. From the head 9 this 35 uid returns through a second group I0 of tubes 2 to an outlet chamber II and an outlet I2. The arrangement is such that neither fluid comes into direct contact with the other, except through the wall of the tubes 2 or the floating head 9. 40

For the purpose of the heat exchange being accomplished between two uids, it makes little difference which fluid passes through the shell and which passes through the tubes, but when heat is transferred between a liquid and av gas 45 or vapor, the gas or vapor is usually passed into the shell and the liquid forced through the tubes. The particular form of heat exchanger to which the present invention is applied is that form in which the tubes2 are secured at their ends to a 50 pair of spaced tube sheets I3 and I4. In this type of heat exchanger, provision must be made for relative expansion between the shell I and the tubes 2, inasmuch vas it is frequently desirable to make the tubes 2 of a diierent metal than 55 60 other viscous that -of the shell I. For example, the tubes 2 might be made of copper and the shell I of steel, and since these metals have different temperature coefficients of expansion, a greater lengthentween the interior of the tube bundles and the v surface of the shell, which difference in temperai 'ture will set up expansion strains.

In the heat exchanger oi' the present invention, this relative expansion is taken care of by the provision of the head 9, which may be described as floating. The head 9, it will be seen, comprises a dome element I5 having a ilat annular ange I6 at its outer periphery.- Flange I8 rests upon the edge of the floating tube sheet I4. On the other side of the tube sheet I4 there is provided a ring I1. Circumferentially spaced bolts I8 clamp the tube sheet I4 between the flange I8 and the ring I1. The shell 2 has, at this end of the heat exchanger, an outwardly extending flange I9, to which is secured, by bolts 20, an outwardly extending fiange 2| of a cap or end closure 22. The floating head 9 is entirely contained within the cap 22, but is free of any attachment thereto. At

the other end of the heat exchanger, the shell 2 is provided with an outwardly extending flange 23. A cylinder 24, having outwardly extending flanges 25/and 26 at each end thereof, to which a closure plate 29 is attached, forms the end closure of the heat,exchanger.

Between the flange 23 of the shell I and the flange 25 of the cylinder 24 is clamped the stationary tube sheet I3, by meansof circumferentlally disposed bolts 2l. To the flange 26 of the cylinder 24 is secured, by means of bolts 28, a relatively fiat closure plate 29. The cylinder 24 includes the inlet 6 and outlet I2, adjacent to each other as shown in Figures 1 and 3, and a vertical baille -30 providing separate inlet and outlet chambers. From this construction, it will be seen that the tubes 2 are rigidly attached to the shell I at one end thereof (the lower end in Figures 1 and 2), but are free of any attachment whatsoever at their other end (the upper end in Figures 1 and 2). Thus, relative expansion may take 'place 50 between the shell I and the tubes 2, without placing either of these elements under compression or stretching strain, since the floating head 9 is permitted to move freely within the cap 22.

It is highly desirable in heat exchangers of 55l thisgeneral construction, that provision be made so that the tube bundle, including the tube sheets I3 and I4 can be removed as a unit .from the shell I for the purpose of occasional repair and the periodical cleaning which the use of oil and liquids entails. For this purpose, in the present construction, the tube sheet I4 is made of such a diameter that it will readily slide through the shell I. The ring I1 is made in several segmental sections. Disassembly may ac- 65 cordingly be effected in the following manner:

The bolts 2|) are first loosened and removed, permitting the removal of the cap 22 from the flange I9. vThe bolts I8 are then likewise loosened and removed, together with the dome element I 5.

, 70 Due to the segmental construction of the ring I1.,

it can likewise be removed. If the bolts 21 are then loosened and removed, the assembly at the lower endof Fig. 1 may be removed from its end of the shell I, and thereupon the tube sheet 75 I3 may be moved in a downward direction in Fig. 1, thereby removing the tube bundle from the shell, inasmuch as the tube sheet I4 readily passes through the shell I.

It is also important, in heat exchangers of this type, that the tube bundle as nearly as possible ll the interior of the shell, so as to prevent short circuiting, by which is meant a tendency of the fluid in the shell to pass along the space between the outer layer of tubes 2 and the inner Wall of the shell, instead of passing into the interior of the tube bundle to contact with the surfaces of the tubes. For this reason, heat exchangers of this type are customarily constructed with the outside diameter of the tube bundle only slightly smaller than the inside diameter of the shell. The tube bundle, accordingly, substantially lls the interior of the shell. Figures 1 and 2 of the drawings are taken at such a section, and are so diagrammatized, that this feature is not illustrated therein, but Fig. 3, which is a cross section, does adequately illustrate this feature.

Another form of short circuiting of the fluid in the shell I that must be avoided, is the passage of said fluid directly from the inlet 3 to the outlet 4 without circulating through the length of the heat exchanger, thus exerting a heat exchange relationship only on the fluid in the tubes 2 in a localized region of the exchanger. For this rea- Son, the longitudinal baille 5 is provided. This baille 5 comprises, generally speaking, a rectangular plate which is positioned in the shell I, and which extends from the tube sheet I3 somewhat beyond the end of the said shell. The baille 5 occupies a dimetrical relationshipgwith respect to the shell I, and is positioned between the two bundles 8 and I0 of tubes 2 hereinbefore mentioned. The baffle 5 divides the shell I, in effect,

linto two compartments.

It is with the construction of the baille 5 that the present invention is particularly concerned. If said baille 5, for example, constituted a simple rectangular plate welded or secured, as by rivets, in position, in the shell I in a relatively permanent manner, it would com'prise an obstacle preventing the removal of the tube bundle in the manner heretofore described. On the other hand,

Aif the baille 5 comprised a rectangular plate at-l tached merely at its end to the tube piece I3,

whereby it could be removed with the tube bundle, it would, in all probability, make poor contact with the walls of the shell I when in its operatingposition, permitting much leakage of the fluid in theshell I past the baille along the \walls of the shell. This is a form of short circuit- (ing that should be avoided. The baille 5 of the present invention is constructed in such a manner as to overcome the above diiliculties.

Referring more particularly to Figures 2, 3, and 4, it Will be seen that, the baille 5 comprises a pair of rectangular plates 3|. Each of the plates 3| is substantially the same length as the shell I, including both the ilanges I9 -and 23, but is in width somewhat less than the diameter of the shell I. Between the plates 3| is positioned a rectangular frame made up of longitudinal spacer bars 32 and end spacer bars 33 and 34. The end bar 33 is positioned at the extreme end of the plates 3|, while the. end bar 34 is slightly displaced inwardly from the lower end'of the plates 3|. 'Ihe longitudinal bars 32 are spaced inwardlyv a considerable distance from the longitudinal edges of the plate 3| Rivets 35 hold 'the plates 3| and the bars 32, 33, and 34 in permanent, rigid, parallel relationship. Theplates 3| are thereby spaced apart a distance equal to the thickness of the bars 32, 33 and 34, all of which are of substantially the same thickness.

i plates 3|, as indicated at numeral 36.

Numerals 36 indicate longitudinal filler bars, which are sufciently thinner than the spacer bars 32 to slide freely between the two 'plates 3|. The filler bars 36 are positioned between the plates 3| near the longitudinal edges of said plates. At the lower end of the heat exchanger, the i-lller bars 36 are pivoted to the plates 3| by means of bolts 31. The upper ends of the filler bars 36 project somewhat beyond the end of the To the -outer edges 39 of the `iiller bars 36 are afilxed, by means of screws 40 (see Fig. 4), strips of compressible gasket material 4I. The heads of the screws 40 are desirably countersunk a considerable distance below the outer edge of the gasket strips 4I, as indicated in Fig. 4. The outer edges 42 of the gasket strips 4I project beyond the longitudinal edges of the plates 3|.

The plates 3|. are mounted at their lower end upon the stationary tube sheet I3 by means of clips 43 (see also Fig. 5) welded at right angles to the plate 3|, as indicated at numeral 44, ,and

25 studs 45 passing through the clips 43 and into the stationary tube sheet' I3. These constitute the sole permanent supporting means for the plates 3|. ,A block of compressible gasket material 46, still referring to Fig. 5, is desirably inserted be- 30 tween the edge of the spacer block 34 and the tube sheet I3, in order to effect a substantially liquid-proof joint between the plates 3| and the stationary tube sheets I3. The seal is in part secured by screwing down the studs 45 in such a 35 manner as to compress the gasket block 46 against the stationary tube sheet I3.

The bolts 31, which attach the lower end of the ller bars 36 to the plates 3|, desirably slide in lateral slots 41 provided in plates 3|, in order 40 that a degree of lateral adjustment of the illler bars 36 may be effected at this end of the exchanger.

To the ends 38 of the iiller bars 36 projecting beyond the upper ends of the plate 3| are tight- 45 ly secured, by means of bolts`48 (see Figs. 2, 6

and '7), U-shaped clips 49. The projections 33 are embraced between the legs of the clips. To the exteriors of the bends of the clips 43 are Welded, as indicated at numeral 50, interiorly 50 threaded collars 5I. V'I'.he collar 5I on one of the clips 49 carries a left-hand thread, While the collar 5I on the other clip.49 carries a right-hand thread. Numeral 52 indicates a rod which has a threaded portion 53 on each end thereof. One of the threaded portions 53 has a right-hand thread, and ts in the collar 5I having the corresponding thread, while the other portion 53 has a lefthand thread and fits into the left-hand'threaded collar 5I. The outer end of the threaded portion 53 is provided with a- Wrench-receiving polygonal head 54.Y It Will readily be seen that when the rod 52 is turned in one direction, the ller bars 36 are moved outwardly from between the plates 3|, pivoting upon the bolts 31, while when the rod 52 is rotated in the opposite direction, said ller bars Pare moved inwardly. The overall length of the rod 52 is less than the inner diameter of the shell- I.

The disassembly of a heat exchanger embody- )ing such a baille5 constructed In the manner described is eiected in the following manner:

By rotating the rod 52 in such a direction as to draw the ller bars 36 together (which may be done by applying a wrench .to the polygonal por- 7 5 tions 54.after the cap 22 hasl been removed from the heat exchanger) .the pressure exerted by the gasket strips 4I on the interior walls of the shell I is released. Thereupon, the heat exchanger may be disassembled in the manner heretofore indicated, the baille 5 being removed from the heat exchanger along with the tube bundle. The bolts 31 may be adjusted to such a position that the lower ends of the gasket strips 4I are brought into tight engagement with the shell I or the flange 23, upon assembly. This tight engagement at one end does not prevent the ready insertion of the baille 5 into the shell I, because the other ends of the ller bars 36 are drawn inwardly so that gasket strips 4I do not bear against the shell walls. After such assembly, the rod 52 is turned in such a direction as to move the iiller bars 36 outwardly, whereupon the gasket strips 4| are brought into tight, liquid-proof engagement with the walls of the shell substantially throughout their length. The tightening means,

.it will readily be seen, is available for manipuat the inlet 3 spreads and'ilows in two directions,

part of the fluid flowing toward one end of the heat exchanger and the 4other part'ilowing towards the other end. The baille 5 is so arranged that it is by-passed by fluid at each end of the heat exchanger, the two streams of fluid then converging and flowing out of the shell I through A the outlet 4.

In this embodiment, the baille 5 is substantially identical to the bafde of the Fig. 2 embodiment,

except that the filler bars 36 project at each endv beyond the end of the plate 3|. Each end of each bar 36 is now provided with an adjusting rod 52, and all of the parts associatedtherewith. A boit 31, sliding in slots v41 in the plates 3|, is now provided for each end of each bar 36. In this embodiment, the baie 5 is in no way at- Ytached to the stationary tube sheet I3.

In this embodiment, disassembly f the heatI exchanger is accomplished in the following manner, assuming the elements originally to be in their Fig. 8 position.

The cap 22 is removed by removing the bolts 20. The rod 52 at the upper end of the heat exchanger is then available for manipulation,

"and it is rotated in such a manner'that the ller bars 36 are m'oved inwardly or towards each other. The bolts 21 are then removed, permitting removal of the cylinder 24 from the lower end of the heat exchanger. Thereupon, the stationary tube sheet I3u is freed, and may be drawn outwardly from the shell until the iioating tube sheet I4 abuts the rod 52, it being assumed that the dome Il and ring I1 have meanwhile been l removed by removing the bolts I8. In this position, suiiicient space is available for a hand wrench to be inserted into the lower end of the shell I for the purpose of rotating the lower rod 52 in a suitable direction to draw the lower ends of the filler bars 36 inwardly. The upper ends of the bars 36 having already been drawn inwardly, this results in the complete freeing of the baille 5 from the walls of the shell I. Thereupon, the entire tube bundle Lmay be withdrawn from the shell I, drawing the baille 5 along with it.

In this embodiment, the bolts 31 are preferably i those just described in connection with the disassembly oi the embodiment.

, Fig. 9, which is a sectionsimilar to Figures 2 and 8, shows a third embodiment of the invention. In this embodiment, the baille 6 is made up of the customary rectangular plates 3|, together with the spacer bars 32, 33 and 34. The spacer bars 32, 33 and 34 of this embodiment, however, constitute a relatively small rectangle located well towards the center of the plates 3|. Filler bars 36 are, as heretofore, positioned between the -plates 3| at their longitudinal edges, and the construction of the filler bars 36, with their gasket strips 4|, is the same as that heretofore described. However, in this instance the entire length of the llei` bars 36 is included between the ends of the plates 3|; in other Words, the bars 36 are shorter than the plates 3|. In this embodiment, as in the Fig. 2 embodiment, the lower ends .of the plates 3| are secured to the stationary tube sheet I3 by means of clips 43 and bolts 45. A lateral ller bar |34 with an attached gasket'strip 46y is also provided to seal the plates 3| to the stationary tube sheet |3, and, in the present embodiment, this lateral iiller bar |34 is held in position on the plates 3| by bolts 60. The bolts 45 compress the gasket strip 46 35 in the sane manner as in the Fig. 1 embodiment.

As in the Fig. 8 embodiment, a bolt 31 is provided at each end of each illler bar 36, each of the bolts 31sliding in slots 41 in the plates 3|.

Numerals 62 and 63 indicate camming pieces that are rotatably mounted on pivot bolts 64 and 65, respectively, and which are positioned in the space between the two plates 3|. The camming pieces 62 and 63 have curved edges 66 on each side thereof, the curvature of the edges 66 being at increasing radii such that when the pieces 62 and 63 are rotated in one direction (clockwise, for example, in Fig. 9) the edges 66 engage the inner edges of the filler bars 36 to move said ller bars outwardly against the walls of the shell When said pieces 62 and 63 are rotated in the other directionthe outward pressure on the filler bars 36 is relieved and said bars are permitted to move inwardly towards each other by the resilient expansion oi'Y the gasket strips4|. The camming piece 63. has a pair of notches 61 along its inneredge. The camming piece 62 has a pair of oppositely facing notches 68 along its inner edge. Supported between each notch 61 and its corresponding notch 68 is a bar 69. The bars 69 complete a parallelogram relation between the pieces 62 and 63, so that when one f said pieces is rotated, the other piece i s obliged to rotate through a corresponding angle. o The camming piece 63 has a forward triangu- 65 lar projection 10, the point oi which projects beyondl the ends of the plates 3|. Bolted to the projection 10 by means of a bolt 1| is a U-shaped piece 12, which is similar to the device shown in Figures 6 and 7 for the Fig. 1 embodiment. To the bend of the U-shaped member 12 is welded an interiorly threaded collar 13, comparable to the collar 5| of Figures 6 and 7.

Referring to Figures 11 and 12, in additionI to Fig, 9, will be seen that fiat pieces or blocks 14 i extend from the upper end o! the plates 3| near freely in the collars 16.

the longitudinal edges theeoi', the pieces 14 being rigidly mounted between the plates 3| by bolts 16. To the outer end oi' the blocks 14 are welded collars 16. The collars 16 (shown in Figures 11 and 12) are not threaded interiorly, but the collar 13 of Fig. 9 is internally threaded.

Numeral 11' indicates a centrally threaded rod which has unthreaded end portions 18 of reduced diameter. The extreme ends of the portions 18 are provided with wrench-receiving polygonal heads 19. The unthreaded portions 18 rotate 11 of the rod engages the interiorly threaded collar 13 on the U-shaped clip 12.

The overall length of the rod 11 is less than the diameter of the shell, so that said rod. 11

may be drawn through the shell in removing the baiiie from the heat exchanger in the manner heretofore described.

When the rod 11 is rotated, as by applying a wrench to either of the polygonal heads 19, the collar 13 is compelled to move longitudinally on said/rod 11. t Longitudinal movement of the collars 13 is transmitted, through the U-shaped clip 12 and the bolt 1|, to the causing rotation of said pivot 65. As has been explained, the `camming piece 63 cannot rotate without causing a coextensive rotation of the camming piece 62.

The use of this embodiment of the invention will be obvious from the description of the prior embodiment.

. The embodiment of Fig. 9 offers a measure of superiority over the embodiment of Fig.v 2, in that, because the action of camming pieces 62 and 63, the filler blocks 36, and hence the gaskets 4|, are moved inwardly and outwardly ina uniform manner from end to end, instead of being pivoted as in the Fig. 2 embodiment. This eliminates the chance of whatever slight diiliculties might be encountered through the tight binding of the lower end of the illler bars 36, for example, in the Fig. 2 embodiment. The Fig. 9 embodiment is assembled and disassembled in precisely the same manner as the Fig. 2 embodiment.

Fig.` 13 illustrates an embodimient of the invention which bears the same relation to the embodiment of Fig. 9 that the embodiment of Fig.

of Fig. 2; in other 5 in the Fig. 13 embodiment is` 8 bears to the embodiment words, the baille made shorter, and has nopermanent attachcamming piece 63, camming piece on the..

'I'he threaded portion ment to the stationary tube plate |3. In this i embodiment, an opening is provided at each end of the baiiie 5 for the circulation of iiuid in the shell as in the Fig. 8 embodiment. This assumes, of course, that the inlet and outlet 3 and 4v for the shell are positioned near the center of said shell.

Assembly and disassembly of this embodiment, which is comparable to the embodiment of Fig. 8, isy considerably simpler than the assembly and disassembly of the Fig. .8 embodiment. For example, in this embodim'ent, disassembly may be effected by the following sequence ofoperations:

The cap 22 is rst removed, after which the dome element |5 and the ring |1 of the floating head are likewise p then rotated,V by application' of a. wrench to one of the polygonal heads 19, in such a direction that the camming pieces 62 and 63 are rotated to relieve the pressure forcing the ,ller bars 36 outwardly against the shell wall. Thereupon. the stationary head |3 may be drawn away from the shell pulling the baille 6 along with it. As-

removed. The rod 11 is 40 at lthe longitudinal out the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above descripl0 tion or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. In heat exchange apparatus of the class described, a removable baffle comprising a pair of rectangular plates, spacer bars secured between said plates in such manner as to establish said plates in fixed, parallel spaced relationship, filler bars positioned between said plates at the longitudinal edges thereof, and means available for manipulation outside of the confines of said plates for moving said spacer bars towards each other and inwardly from the longitudinal edges of the plates, or away from each other and outwardly from the longitudinal edges of the plates, said last-named means comprising portions of said ller bars projecting beyond the ends of said plates, interiorly threaded collars supported on said portions, and a screw element engaging both of said collars, said collars being threaded in opposite direction, and said screw element having portions threaded in the proper direction for engaging the respective collars.

2. In heat exchange'apparatus of the class 35 described, a removable baille comprising a pair of rectangular plates, spacer bars secured between said plates in such manner-as to establish said plates in fixed, parallel spaced relationship, ller bars positioned between 'said plates edges thereof, and means available for manipulation outside of the coniines'of said plates for moving said spacer bars K towards each other and inwardly from the longitudinal edges of the plates, or away from each other and outwardly from the longitudinal edges of the plates, said last-named means comprising portions of said filler bars projecting beyond the ends of said plates, interiorly threaded collars supported on said portions, and a screw element engaging both of said collars, said collars being threaded in opposite direction, and said screw element having portions threaded inthe proper direction for engaging the respective collars, and means pivoting 'the filler bars to the plates at the other ends of said ller bars.

3. In heat exchange apparatus of the class described, a removable baffle comprising a pair of rectangular plates, spacer bars secured between said plates in such manner as to .establish said plates in fixed, parallel spaced relationship, filler bars positioned between said plates at ythe longitudinal edges thereof, and means available for manipulation outside of the connes of said plates for moving said spacer bars towards each other and inwardly from the longitudinal edges of the plates, or away from each other and outwardly from the longitudinal edges'of the plates, said last-named means comprising portions of each filler bar extending from each end of said plates, interiorly threaded collars mounted on each of said projecting portions, and a threaded rod at each end of said plates engaging the collars on the filler bars at that end of the plates, the collars of the respective filler bars being threaded in opposite directions, and the threaded rods having portions threaded in opposite directions to engage the oppositely threaded collars.

4. In heat exchange apparatus of the class described, a removable baille comprising a pair of rectangular plates, spacer bars secured between said plates in such manner as to establish said plates in fixed, parallel spaced relationship, filler bars positioned between said plates at the longitudinal edges thereof, and "meansI available for vmanipulation outside o f the confines of' said plates for moving said spacer bars towards each other and inwardly from the longitudinal edges of the plates, or away from each other and outwardly from the longitudinal edges of the plates outwardly, said last-named means comprising camming plates pivotally mounted between said rectangular plates, the edges of said camming plates abutting the inside edges of said filler bars, whereby, upon rotation of said camming plates, said filler bars are forced outwardly to an increasingly great extent.

5. In heat exchange apparatus of the class described, a removable baille comprising a pair of rectangular plates, spacer bars secured between said plates in such manner as to establish said plates in fixed, parallel spaced relationship, iiller bars positioned between said plates at the longitudinal edges thereof, and means` available for manipulation outside of the confines of said plates for moving said spacer bars towards each other and inwardly from the longitudinal edges of the plates or away from each other and outwardly from the longitudinal edges of the plates, said last-named means comprising camming plates pivotally mounted between said rectangular plates, the edges of said camming plates abutting the insideedges of said filler bars, whereby, upon rotation of said camming plates, said filler barsare forced outwardly to an increasingly great extent, and means for rotating said camming plates available for manipulation outside lof the confines of said rectangular plates.

VIVUS O. MARSHALL. 

